Method of manufacturing commutators



Sept. 6, 1927. 1,641,414

RI M. CRI TCHFIELD H METHOD OF MANUFACTURING COMMUTATORS Filed Dec. 15, 1924 m ma Sept. 6, 1-927.

UNITED STATES ROBERT M. CRITCHFI ELD, OF ANDERSON,

PATENT OFFICE.

INDIANA, assrenoa, 3r amsnn ASSIGN- unn'rs, T DELCO-REMY conrona'rron, or DAYTON, 01110, A conrona'rlon or DELAWARE.

Application filed December 13, 1924. Serial No. 755,810.

This invention relates to commutators and the manufacture thereof, and more particularly to small commutators such as are used in small electric motors for motor-operated automobile horns. g r

The objec'ts'of the invention are to simplify and improve the-construction of commutators of this type whereby to reduce the cost of manufacture.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanyin drawings, wherein a preferred form of t epresent invention is clearly shown.

In the drawings: I

Fig. 1 is an edge view of a previously formed strip of copper or other conducting material-used in the manufacture of commutatorsaccording to the resent invention;.Fig. 2 is a plan view t ereof; Fig. 3 is an end view in the direction of arrow 3 in Fig. 2; Fi 4 is an end viewof a ring constructed 0 metal shown in Figs. 1, 2 and 3; Fig. 5 is a view partly in longitudinal sec tion showing a commutator constructed in accordance'with the present invention; and

Fi ,6 is an end view of the commutator "anc shaft shown in Fig. 5. Figs. 1' to 4 are drawn on a larger scale than Figs. 5 and '6 in order to show more clearly certain novel features.

Referring to the drawings, the commutators are 7 constructed from predetermined lengths of malleable, ductile metal of good electrical conductivityv shown in Figs. 1, 2 and 3. This material is formed by providing a bar 20 of copper with a plurality of parallel grooves 21 which space a plurality of tangs, 22. The surfaces 23 of the bar be tween the tangs 22 are corrugated or ribbed in a direction parallel to the long dimension of the bar 20, or transversely to the side operation causesthe concave surfaces 25 of the tangs 22 to be rendered more nearly plane thus causing the tangs 22'to be rendered dove-tailed sha in cross section. A central support or sha 32 for supportin the commutator is provided with a knurle lite molding powder is tamped into the space in the mold between the cylinder 30 and the shaft 32. The molding material is sub-' jected to heat andflpre'ssure to cause it to take a permanent form and to flow sufiiciently to fill the spaces 34 of the cylinder 30 between the dove-tail tangs 22, the spaces between the ribs or corrugations of the surfaces-23 and the spaces provided b knurls 33 and groove '33 of the sha 32. In this .manner, cylinder 30 is firmly anchored to the shaft 32.

'- The next operation is to separate the cylthe inder 30 lengthwise into segments. This is I done preferably by sawin the metal, one

.of the saw cuts being ta en throu h "the abutting surfaces of the cylinder as in icated byline 31. This 0 eration divides the cylindei' into a%* lu'ra ity of segments 35 anchored to a' ody 36 of molded material which in turn-is anchored to the shaft 32. Each segment 35 is rovided with a notch 37 for receiving a lea from an armature coil (not shown), the armature. being also mounted on theshaft 32.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form it is to be understood that other forms mlght be adopted, all coming within the sec e of the claims which follow.

What is claimed is as follows: 1'. The method of making a commutator which includes makingametal cylinder having inwardly projecting spaced tangs extending longitudinally of the cylinder, in locating a support centrally of the cylinder and spaced therefrom, in joining the support and tangs by a non-conducting hardenable plastic material andin separating the cylinder longitudinally into segments to provide an annulus of insulated metal bars.

I. '2. The method of making a commutator which includes making a metal cylinder having inwardly projecting spaced tangs, dovetall-shape in transverse section and extending longitudinally of the cylinder, in locating a support centrally of the cylinder and spaced therefrom, in joining the support and tangs by a non-conducting hardenable plastic material, and in separating the cylinder longitudinally into segments to provide an annulus of insulated metal bars.

8 The method of making a commutator which includes forming a fiat bar of metal with a plurality of spaced parallel tangs, in bendin the bar -into a cylinder with meeting edges aiutting and in deforming the faces of the tangs transversely so that the face will be wider than the width of the tang adjacent the main portion of the cylinder, in locating-a support centrally of the cylinder and spaced therefrom, in joining the support and tangs by a non-conducting hardenable plastic material, and in separating the cylinder longitudinally into segments to provide an annulus of insulated metal bars.

4:. The method of making a commutator which includes forming a flat bar of metal with a plurality of spaced parallel tangs, the

tangs more nearly planelso that the face will be wider than the width of the tang adjacent the main portion of the cylinder, in locating a support centrally of the cylinder and spaced therefrom, in joining the support and tangs by a non-conducting hardenable plastic material, and in separating the cylinder longitudinally into segments to provide an annulus of insulated metal bars.

5. Material for making cominutators, consisting of a bar of ductile metal of good electrical conductivity grooved on one side to provide parallel tangs having concave faces.

6. Material for making commutators, consisting of a bar of ductile metal of good electrical conductivity grooved on one side to provide parallel tangs the surfaces of the bar between the tangs being provided with ridges transverse to the side walls of the tangs.

In testimony whereof I hereto afiix my signature.

R. M. CRITCHFIELD. 

